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Durum

This article is about the cultivar of wheat. For the Turkish döner wrap, see dürüm.

Durum wheat[2] (/ˈdjʊrəm/), also called pasta wheat[3] or macaroni wheat (Triticum durum or Triticum turgidum subsp. durum),[4] is a tetraploid species of wheat.[5] It is the second most cultivated species of wheat after common wheat, although it only represents 5% to 8% of global wheat production.[6] It was developed by artificial selection of the domesticated emmer wheat strains formerly grown in Central Europe and the Near East around 7000 BC, which developed a naked, free-threshing form.[7] Like emmer, durum wheat is awned (with bristles). It is the predominant wheat that grows in the Middle East.

Durum in Latin means "hard", and the species is the hardest of all wheats. This refers to the resistance of the grain to milling, in particular of the starchyendosperm, implying dough made from its flour is weak or "soft". This makes durum favorable for semolina and pasta and less practical for flour, which requires more work than with hexaploid wheats like common bread wheats. Despite its high protein content, durum is not a strong wheat in the sense of giving strength to dough through the formation of a gluten network. Durum contains 27% extractable, wet gluten, about 3% higher than in common wheat (T. aestivum L.).[8]

Commercially produced dry pasta, or pasta secca, is made almost exclusively from durum semolina.[11] Most home made fresh pastas (pasta fresca), such as orecchiette and tagliatelle, also use durum wheat or a combination of soft and hard wheats.

Durum flour and semolina are good for making pasta because it does not create doughs hard to shape, e.g. into sheets. Technically, the dough is relatively plastic, contrasting with the strong elastic doughs obtained from bread flours. The French language differentiates strength (force) from hardness (dureté), resolving a contradiction present in English language presentations: durum is rich in gluten but that is not readily available as the endosperm is hard to break to release that gluten. Durum wheat is thus less used in breadmaking. Its protein content is almost as high as that of hard spring or winter wheat and so is its gluten content, necessary for bread to rise. Although 100 percent durum wheat breads do exist (such as pagnotte di Enna or "rimacinato" bread from Sicily, as well as Altamura bread from Apulia and Matera bread from Basilicata) in most instances bread doughs contain only a portion of durum wheat and are supplemented substantially with commercial white flours, often those higher in gluten necessary to offset the poor contribution of durum flour to the gluten network. Pure durum wheat breads are often dense, containing little air bubbles, with relatively little elastic structure (continuum). The uncooked dough splits easily and is easier to shape, as for instance to make pies or pastas.

The use of wheat to produce pasta was described as early as the 10th century by Ibn Wahshīya of Cairo. The North Africans called the product itrīya, from which Italian sources derived the term tria (or aletría in the case of Spanish sources) during the 15th century.[12]

Most of the durum grown today is amber durum, the grains of which are amber-colored and larger than those of other types of wheat. Durum has a yellow endosperm, which gives pasta its color. When durum is milled, the endosperm is ground into a granular product called semolina. Semolina made from durum is used for premium pastas and breads. There is also a red durum, used mostly for livestock feed.

The cultivation of durum generates greater yield than other wheats in areas of low precipitation (3–5 dm). Good yields can be obtained by irrigation, but this is rarely done. In the first half of the 20th century, the crop was widely grown in Russia.[15] Durum is one of the most important food crops in West Asia. Although the variety of the wheat there is diverse, it is not extensively grown there, and thus must be imported.[16] West amber durum produced in Canada is used mostly as semolina/pasta, but some is also exported to Italy for bread production.[17]

In the Middle East and North Africa, local bread-making accounts for half the consumption of durum. Some flour is even imported. On the other hand, many countries in Europe produce durum in commercially significant quantities.[18]

Durum wheat is subject to four processes: cleaning, tempering, milling and purifying. First, durum wheat is cleaned to remove foreign material and shrunken and broken kernels. Then it is tempered to a moisture content, toughening the seed coat for efficient separation of bran and endosperm. Durum milling is a complex procedure involving repetitive grinding and sieving. Proper purifying results in maximum semolina yield and the least amount of bran powder.[20]

To produce bread, durum wheat is ground into flour. The flour is mixed with water to produce dough. The quantities mixed vary, depending on the acidity of the mixture. The dough is mixed with yeast and lukewarm water, and then fermented for hours.

The quality of the bread produced depends on the viscoelastic properties of gluten, the protein content and protein composition.[8][18] Containing about 12% total protein in defatted flour compared to 11% in common wheat, durum wheat yields 27% extractable, wet gluten compared to 24% in common wheat.[8]